Trace element nutrition during pregnancy.
The best means to ensure an optimal intake of trace elements during pregnancy is the consumption of a well-balanced diet that includes both animal- and plant-food sources. Although vegetarian diets provide reasonable sources of trace elements, especially in dried beans and seeds, flesh foods contain higher concentrations of trace elements that are in a more readily absorbable form. Iron is the only trace element for which routine supplementation is recommended. In the United States, the iodine content of the food supply is sufficiently high to make supplementation unnecessary, but use of iodized salt is not contraindicated. There is no need to screen pregnant women routinely for trace element status, except to monitor hemoglobin and hematocrit as an indicator of iron status. The best indicators that a woman's trace element status may be at risk is a history of poor food selections, a clinical disorder that alters trace element use or excretion, or prior residence in a region of the world where the trace element content of the soil is low.